Thursday, May 14, 2009

Articular concerns! Egg White Matrix?

Articular hyaline cartilage

There are many parts in a body and many of them are over looked!
Just wait to see how Kurt/WN/Dartfish is going to "MYTH BUST" in the near future!

The articular surface of the distal tibia (including the lateral surface of the medial malleolus), the articular surface on the medial aspect of the fibular malleolus and the articular surfaces on the upper, lateral and medial aspects of the body of the talus are covered by a variety of hyaline cartilage termed articular hyaline cartilage. These surfaces collectively constitute the talocrural (or ankle joint) which is a synovial articulation.

Articular hyaline cartilage also covers the articulating surfaces of all the other synovial articulations in the foot, namely, the talocalcaneal joint, the talocalcaneonavicular joint, the calcaneocuboid joint, the tarsometatarsal articulations, the metatarsophalangeal articulations, and interphalangeal articulations. Over compression of any of these joints can cause issues in your cycling.  Far too often, someone or some device wants you to change the shape of your foot?  Your bones and joints need to maintain their true to form shape i.e. a flat foot doesn't need an arch support! In some cases doesn't need a stiff carbon fiber sole, its too stiff and transmits high vibration into your body.  

Articular hyaline cartilage offers a firm, smooth and relatively friction-free surface facilitating joint movements. The thickness of articular hyaline cartilage in the ankle joint is not uniform and varies from 3mm to 5mm. In the smaller joints of the foot, the articular cartilage is no more than 2 mm thick. Articular hyaline cartilage possesses a degree of compressibility and elasticity. The foot is very much like a truss, a roman bridge, so a high arch is very much like a flat foot, the truss system is well loaded and how it interfaces the pedal is of concern.  These features enable the articular surfaces to dissipate laterally the axial compressive forces to which the joints are subjected. This is especially useful in such weight-bearing joints as the talocrural and talocalcaneal articulations. Articular hyaline cartilage does not usually ossify, but with age and in the semi weight-bearing of cycling there is enough force to retard (stiff chain links) your performance.

The surface of articular hyaline cartilage is lubricated by synovial fluid secreted by the synovial membrane (knee) lining the inner surface of the joint capsule. However, the articular cartilage itself is not covered by synovial membrane. As with hyaline cartilage in extraarticular sites, the substance of articular hyaline cartilage is made up of cells termed chondroblasts and chondrocytes, and an intercellular matrix elaborated by the chondrocytes. The intercellular matrix is biochemically complex, and is composed of various proteins including different types of collagen, a variety of cell adhesion molecules and glycosaminoglycans, and lipids. It feels much the same as the matrix of raw egg white. The glycosaminoglycans are arranged systematically about a core protein to form complex hydrophilic molecules termed proteoglycans. The proteoglycans are chiefly responsible for the impressive viscoelastic biomechanical properties of articular cartilage.

Healthy articular hyaline cartilage in the young individual has a pale and glistening appearance, and a firm and smooth texture.  In other words, it can take beating, or provide more protection. With age degenerative changes begin to appear, and cartilage loses its smooth and glistening character, thus loosing its protection within a joint.  With age and abuse, the gaps between the joints need even more attention to live an active life style i.e. cycling.

At the histological level, a more indepth look at articular hyaline cartilage is seen to be made up of four layers or zones on the basis of differences in cellular morphology, cellular density as well as differences in the composition of extracellular matrix. 

Of the four layers, the most superficial layer faces the joint cavity, and the deepest layer is apposed to, and fused with, the subchondral bone.

From superficial to deep, these layers are named as follows:

i) Tangential stratum (Zone 1)

ii) Transitional stratum (Zone 2)

iii) Radiate stratum (Zone 3)

iv) Calcified stratum (Zone 4)

The region between Zone 3 and Zone 4 is called the tidemark and is readily discernible in young cartilage within all large synovial joints, including the ankle joint. The progressive ossification of Zone 4, which accompanies aging, results in the blurring of the tidemark.

Articular hyaline cartilage is devoid of innervation and lymphatic vessels. Except for the presence of a few blood vessels in Zone 4, articular hyaline cartilage is also normally devoid of vascularity, and is believed to derive its nutrition mainly by diffusion from synovial fluid and from the vascular plexus in synovial membrane.

The area of the ankle is very hard to get your brain around and understand what is the best pedal stroke.  However it is just like thinking of the wrist and the golf culb making the best contact to the ball. The wrist angle is important and so is the ankle angle.  Take a person who uses a hammer wrong all day and they will also hurt.  Even a poor fly cast, or poor tennis stroke can cause issues. Too many people just go out and swing the club (pedal) any old way they wish, then wonder why they suffer in performance and recovery. You are not going to score well if you don't start thinking about what causes issues and work on refining them. 

You are striking the pedal about 5,000 times per hour in a semi-weigth bearing fashion, so if your cleat/pedal setup is off just a little you will pay. The shock waves that come from a poor interface can move through the bones, then to another joint i.e. knee, hip, spine, etc...

I know this is over the top, but think of this model.  Think of placing your cleat on the top of your shoe, rather than under i.e. 1 - 2 inches in the wrong place?  Think about how that placement of cleat orbits in space around your chain ring?  Think about how the leg links and saddle options affect the orbit?  I think you now can see how far off people can be!  Even a few mm off can affect you human link chain!

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